1. Field of the Disclosure
The present invention relates to a light emitting diode (LED) lamp assembly including an integrated electronic ballast and a thermal management system.
2. Related Art
Incandescent light bulbs, or lamps, have been in existence for over 100 years and are the primary type of light source used in a wide variety of lighting applications. For example, incandescent light bulbs are commonly used in a residential setting whether in recessed downlight ceiling fixtures or standard table lamps. Incandescent lamps give off light from a filament that is heated in a process known as incandescence. However, incandescent lamps have very low efficiency. Only about 5% of the electricity provided to the lamps is used to produce light, the remaining 95% is wasted as heat. Recently, the development of the compact fluorescent lamp (CFL) has offered improved efficiency. CFLs typically convert about 25% of the energy applied to them to light with only 75% being lost as heat. Thus, about five time less energy is required to provide an equivalent amount of light in a CFL when compared with an incandescent lamp. That is, a 12 watt CFL will provide roughly the same amount of light as a 60 watt incandescent lamp. CFL's also generally last about 5 times longer than incandescent lamps, as well. Typically, an incandescent lamp will have a 2000 hour lifetime while a CFL generally has a 10,000 hour lifetime.
CFLs are already popular in commercial applications such as hotels and other commercial spaces, due to the savings they can offer in energy use and in increased lifetime. One disadvantage of CFLs, however, is the quality of the light produced. CFLs produce light that has a different spectrum compared to incandescent lamps. As a result, CFLs do not provide the same warm white color that incandescent lamps provide and thus are typically not favored in residential environments. In addition, CFLs require a longer turn-on and warm up time as well. Further, CFLs are typically not dimmable using standard phase-cutting wall dimmers, and thus, may not be easily incorporated into existing lighting systems. CFLs also require electronic ballasts between the AC mains voltage and the lamp to control lamp power. The electronic ballasts tend to be unreliable since they must operate at relatively high ambient temperatures. Temperature management is particularly important when they are used in a downlight fixture, for example, where heat rises up into the fixture and cannot escape. These disadvantages have slowed the adoption of CFLs for other applications despite the efficiency advantages that are available using these lamps.
The light emitting diode (LED) has recently been gaining popularity in various lighting applications as improved technology has resulted in an increase in lumens/wattage available in LEDs. LED's create light at the p-n junction of a solid state semi-conductor diode. Advancements in technology have resulted in semi-conductor materials and packaging techniques that have increased the amount of light output from the diode junction, while minimizing losses across the junction. Theoretically, LEDs may be able to provide up to 90% efficiency and a lifetime of 100,000 hours. Thus, LEDs have the potential to offer vastly improved efficiency in comparison to both incandescent lamps and CFLs. High brightness LEDs have already been developed that match fluorescent lighting in lumens/watts and are being used more and more in various applications, such as in traffic lights, signage, emergency lighting, backlighting and street lighting. One disadvantage of LEDs is that they include no true white color and no thermal management. In addition, it typically requires a relatively high number of LEDs to provide sufficient light coverage for any particular desired area. LEDs also require a regulated power supply as well.
As LED technology advances, it will likely be possible to provide white colored light with an LED. In addition, efficiency increases will likely lead to a reduction in the number of LEDs necessary to provide sufficient light coverage for any particular area. However, thermal management concerns will still need to be addressed. Until thermal management issues are resolved, less efficient, but reliable and safe incandescent lamps will likely remain dominant in residential lighting applications.
Accordingly, it would be desirable to provide an LED lamp assembly including an integral electronic ballast and thermal management system.